Cyclone dust collector

ABSTRACT

Provided is a cyclone dust collector with a higher particle collection efficiency than before. The cyclone dust collector of the present invention includes a nozzle assembly including a plurality of the nozzles arranged within a first cross section defined by a plane containing a center axis of the cylindrical case and part of the spiral flow path intersecting with each other, the nozzles being adapted to spray the water mist in a direction along the first cross section.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a cyclone dust collector, whichincludes, inside a cylindrical case, a spiral flow path defined by aspiral guide and a nozzle that sprays water mist, to combine particlesto be removed that are contained in an air passing through the spiralflow path with the water mist and to centrifugally collect the particleson an inner surface of the cylindrical case.

Description of the Related Art

As a cyclone dust collector of this type, one that includes a pluralityof spray nozzles dispersedly arranged in a regular pattern along aspiral flow path has been known before (see, for example, FIG. 2 ofJapanese Patent Application Publication No. 2015-020129A).

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, the particle collection efficiency of the cyclone dustcollector described above is not high enough, and the improvementthereof has been desired.

The present invention was made in view of the circumstance describedabove and it is an object of the invention to provide a cyclone dustcollector with a higher particle collection efficiency than before.

The cyclone dust collector according to one aspect of the presentinvention made to achieve the object noted above includes, inside acylindrical case, a spiral flow path defined by a spiral guide and anozzle that sprays water mist, to combine particles to be removed thatare contained in an air passing through the spiral flow path with thewater mist and to centrifugally collect the particles on an innersurface of the cylindrical case for recovery. The cyclone dust collectorincludes a nozzle assembly having a plurality of the nozzles arrangedwithin a vertical cross section defined by a plane containing a centeraxis of the cylindrical case and part of the spiral flow pathintersecting with each other, the nozzles spraying the water mist withinthe vertical cross section.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a cyclone dust collector according to afirst embodiment of the present invention;

FIG. 2 is a perspective view of a constricted part forming member;

FIG. 3 is a partially enlarged perspective view of a nozzle assembly;

FIG. 4 is a perspective view of a constricted part forming memberaccording to a second embodiment;

FIG. 5(A) and FIG. 5(B) are perspective views of constricted partforming members according to a third embodiment;

FIG. 6 is a perspective view of a constricted part forming memberaccording to a fourth embodiment;

FIG. 7 is a side cross-sectional view of a constricted part formingmember according to a fifth embodiment;

FIG. 8(A) is a first distribution diagram of particulate 1 and FIG. 8(B)is a second distribution diagram of particulate 2, according to ExampleProduct 1; and

FIG. 9(A) is a first distribution diagram of particulate 1 and FIG. 9(B)is a second distribution diagram of particulate 2, according toComparative Product 1.

DESCRIPTION OF THE EMBODIMENTS First Embodiment

Hereinafter, a first embodiment of the present invention will bedescribed with reference to FIG. 1 to FIG. 3. The cyclone dust collector10 of this embodiment is used for purifying the air exhausted from acoating booth (not shown). Inside the coating booth, a coating robotperforms coating by spraying atomized paint (hereinafter referred to as“paint mist”) to a workpiece. The ceiling of the coating booth is in theform of mesh, while the floor takes the form of duckboards. The spacebeneath the floor is divided into upper and lower halves by anintermediate plate, which has a plurality of through holes, and holdswater on the intermediate plate. The air flowing down from the entireceiling travels down below the floor with the unused paint mist. Part ofthe paint mist is captured in the water on the intermediate plate, whilethe air containing the rest of the paint mist is discharged into a gasand liquid exhaust duct 11 extending substantially horizontally from thecompartment below the intermediate plate. The water on the intermediateplate also drops down through the through holes and flows into the gasand liquid exhaust duct 11 below.

As shown in FIG. 1, the cyclone dust collector 10 of this embodimentincludes a cylindrical case 12 that stands upright on a distal end partof the gas and liquid exhaust duct 11. The lower end of the cylindricalcase 12 is open and communicates with the interior of the gas and liquidexhaust duct 11. A ring-shaped inward flange 13 extending inward isprovided to the upper end of the cylindrical case 12, and the inside ofthis inward flange 13 serves as an exhaust port 13A of the cyclone dustcollector 10. The air containing paint mist flows into the cylindricalcase 12 from its lower end, and the air from which the paint mist hasbeen removed flows out from the exhaust port 13A at the upper end. Inthis embodiment, the paint mist particles contained in this aircorresponds to the “particles to be removed” according to the presentinvention.

A center pillar 14A is provided in a central part of the cylindricalcase 12. The center pillar 14A has a pipe structure and extends from thelower end of the cylindrical case 12 to a position near the upper end ofthe cylindrical case, and is closed at the upper end. A waterdistribution pipe 14B extends through one side face of the gas andliquid exhaust duct 11 at a position closer to the upper end. A distalend portion of the water distribution pipe 14B is connected to the lowerend of the center pillar 14A. A pump (not shown) supplies water to thecenter pillar 14A via the water distribution pipe 14B. In thisembodiment, the center pillar 14A has a structure of pipe and is usedfor supplying water, however, the center pillar 14A may have a solidstructure and a water supply pipe may be laid along an outer surface ofthe center pillar 14A.

The cylindrical case 12 accommodates a spiral guide 15. The spiral guide15 extends helically around the center pillar 14A about two and a halfturns, for example. Outer edges of the spiral guide 15 contact an innersurface of the cylindrical case 12, so that a spiral flow path 16 isformed inside the cylindrical case 12. An upper end edge 15A of thespiral guide 15 is located closer to the upper end of the cylindricalcase 12. A lower end edge 15B of the spiral guide 15 is positionedwithin an opening plane of the lower end of the cylindrical case 12, andextends in a direction orthogonal to the air flow direction (i.e., widthdirection) in the gas and liquid exhaust duct 11. The lower part of thespiral guide 15 is inclined gradually upward from the lower end edge 15Bin the air flow direction in the gas and liquid exhaust duct 11.

A constricted part forming member 20 is mounted in an upstream endportion of the spiral flow path 16. The constricted part forming member20 includes a support frame 17 fitted to the upstream end portion of thespiral flow path 16. More specifically, the support frame 17 is arrangedwithin a vertical cross section 16A (corresponding to a first crosssection of the present invention), which is defined by a planecontaining the center axis J1 of the cylindrical case 12 and the lowerend edge 15B of the spiral guide 15, and the upstream end portion of thespiral flow path 16 intersecting with the plane.

As shown in FIG. 2, the support frame 17 is structured such that a pairof legs 17B extending in an up and down direction along both side edgesof the vertical cross section 16A are connected at their upper ends byan upper end bridge 17A extending along the upper edge of the verticalcross section 16A, with an intermediate bridge 17C connecting portionssubstantially in the center in the up and down direction of the pair oflegs 17B. One of the legs 17B is fixedly screwed to the center pillar14A, while the other leg 17B is fixedly screwed to the cylindrical case12. The upper end bridge 17A is in contact with the lower face of thespiral guide 15 thereabove. The intermediate bridge 17C further dividesthe vertical cross section 16A into a pair of split regions 51A and 51B.Screw holes in the center pillar 14A for fixing the leg 17B are formedsuch as not to extend through, or tightly sealed with a sealingmaterial. In this embodiment, the intermediate bridge 17C corresponds toa partition bar according to the present invention.

Triangular ribs 18 (corresponding to an inner wall of the presentinvention) are fixed to both corners on the upper side of the supportframe 17. The support frame 17 and triangular ribs 18 make the startingend of the spiral flow path 16 narrower and thus a constricted part 19is formed.

In a central part of the longitudinal direction of the intermediatebridge 17C are provided four nozzles 22 spraying water mist radiallyinside the constricted part 19 and constituting a nozzle assembly 50.More specifically, as shown in FIG. 3, a pair of through holes 21A thatare inclined at 45° to the up and down direction and orthogonal to eachother, for example, extend through in the intermediate bridge 17C. Spraynozzles 22 are screwed in both ends of the through holes 21A. Acommunication hole 21B extends from the intersecting portion of both thethrough holes 21A to the back side of the intermediate bridge 17C, andan elbow joint 23 is attached to the rear end opening of thiscommunication hole 21B. As shown in FIG. 2, a through hole is formed inthe center pillar 14A at a position opposite the elbow joint 23, and astraight joint 24 is attached thereto. The elbow joint 23 and thestraight joint 24 are connected to each other with a pipe P. Water isthus supplied collectively from the center pillar 14A to the fournozzles 22, from which water mist is sprayed radially.

Through holes are formed, with nozzles 30 screwed therein, at positionsin the middle between the spiral guides above and below, at threelocations of the center pillar 14A, 90° helically advanced from theconstricted part 19 along the spiral flow path 16, 180° advanced fromthere, and 180° advanced further from there. A through hole is formed inthe center pillar 14A also at the back of one triangular rib 18, with anozzle 30 being screwed therein. Water inside the center pillar 14A issprayed toward the inner surface of the cylindrical case 12 from each ofthe nozzles 30.

The structure of the cyclone dust collector 10 of this embodiment is asdescribed above. Next, the advantageous effects of this cyclone dustcollector 10 will be described. The air containing the paint mist anddischarged from the coating booth flows into the cylindrical case 12 ofthe cyclone dust collector 10 through the gas and liquid exhaust duct11. Water mist is sprayed toward the air inside the cylindrical case 12.The air containing the water mist and the paint mist moves up spirallyalong the spiral flow path 16. Particles other than the gas molecules inthe air are collected on the inner surface of the cylindrical case 12 bythe centrifugal force of this spiral movement. The heavier the particlesare, the more easily they are collected on the inner surface of thecylindrical case 12, as they are subjected to a larger centrifugalforce. Therefore, to remove the paint mist, it is favorable that paintmist particles and water mist particles combine to grow larger.

If the cyclone dust collector 10 has a structure similar to conventionalones in which a plurality of nozzles are dispersed in a regular patternalong the spiral flow path 16, the water mist particles cannot bedistributed to the entire air and sufficiently mixed with the paintmist. Since the air flows in a laminar way inside the spiral flow path16, the separate paint mist and water mist do not sufficiently mix witheach other as they travel downstream. The paint mist particles and thewater mist particles hardly join each other, which results in a lowerpaint mist particle collection efficiency.

On the other hand, the cyclone dust collector 10 of this embodimentincludes the constricted part forming member 20 and the nozzle assembly50. As shown in FIG. 2, the vertical cross section 16A is divided by theintermediate bridge 17C of the constricted part forming member 20 intotwo, upper and lower, split regions 51A and 51B, and the four nozzles 22constituting the nozzle assembly 50 are separately assigned tosubstantially the left half and right half areas of the upper splitregion 51A and substantially the left half and right half areas of thelower split region 51B for spraying water mist in each assigned area.Namely, the plurality of nozzles 22 can cooperatively spray the watermist substantially over the entire vertical cross section 16A of thespiral flow path 16. This way, as compared to conventional structures inwhich a plurality of nozzles are distributed in a regular pattern alongthe spiral flow path 16, the amount of air that passes through thenozzles without being hit by the water mist can be reduced, and themixing rate of the particles to be removed in the air and the water mistparticles can be raised.

The nozzle assembly 50 is arranged at an upstream end portion of thespiral flow path 16 and the water mist and the paint mist are mixedtogether at an early stage of passage of the air through the spiral flowpath 16. The provision of the constricted part forming member 20 furthercreates turbulence in the air to facilitate the mixing. Since theconstricted part forming member 20 makes the vertical cross section 16Aof the spiral flow path 16 narrower to form the constricted part 19 sothat the air passage area is smaller there than other parts, the watermist can readily be distributed over the entire vertical cross section16A. According to a simulation as will be described later, the watermist can hardly reach corners of the spiral flow path 16. In the cyclonedust collector 10 of this embodiment, triangular ribs 18 are arranged atthe corners of the vertical cross section 16A to reduce areas hardlyreached by the water mist, so that the mixing rate of the paint mistparticles and the water mist particles can be raised efficiently.

As described above, with the cyclone dust collector 10 of thisembodiment, the mixing rate of the paint mist particles and the watermist particles is raised, so that the particles to be removed and watermist particles can join each other more easily and the collectionefficiency of particles to be removed is improved than before.

The plurality of nozzles 22 and 30 inside the cylindrical case 12 areall located closer to the upstream side of the spiral flow path 16, sothat less water mist is discharged to the outside of the cyclone dustcollector 10. This can reduce the possibility of corrosion or waterleakage of the ducts and exhaust fans arranged in the exhaust path ofthe air released from the cyclone dust collector 10. Moreover, thiscyclone dust collector 10 allows the constricted part forming member 20to be removed for easy cleaning of the interior.

Part of the air exhausted from the exhaust port 13 of the cyclone dustcollector 10 is released to the atmosphere, while the rest is fed backto the coating booth for reuse after its moisture and temperature areadjusted by known equipment. The water discharged from the coating boothto the gas and liquid exhaust duct 11 is purified by known equipment andfed to the coating booth, or delivered from the water distribution pipe14B to the center pillar 14A to be reused.

Second Embodiment

This embodiment is illustrated in FIG. 4, and different from the firstembodiment in the configuration of a constricted part forming member20X. More specifically, the triangular ribs 18 are removed from theconstricted part forming member 20 of the above-described firstembodiment in the constricted part forming member 20X. The constrictedpart forming member 20X includes a nozzle assembly 50V having aplurality of nozzles 22 each on the upper face and lower face of theintermediate bridge 17C. The plurality of nozzles 22 on the upper faceof the intermediate bridge 17C spray water mist upward, while theplurality of nozzles 22 on the lower face of the intermediate bridge 17Cspray water mist downward. The configuration of this embodiment alsoprovides the advantageous effects similar to those of the firstembodiment.

Third Embodiment

This embodiment is shown in FIG. 5(A), and configured by removing theintermediate bridge 17C from the above-described second embodiment, witha nozzle assembly 50W having a plurality of vertically aligned nozzles22 each on the opposite faces of the pair of legs 17B. The nozzles 22spray water mist in opposite directions from each of the legs 17B. Theconfiguration of this embodiment also provides the advantageous effectssimilar to those of the first embodiment.

Instead of arranging the plurality of nozzles 22 on the legs 17B of thesupport frame 17 as described above, a plurality of nozzles 22 may bearranged on the upper end bridge 17A of the support frame 17 as in anozzle assembly 50X shown in FIG. 5(B) so that water mist is sprayedtoward the spiral flow path 16 only from above.

Fourth Embodiment

This embodiment is illustrated in FIG. 6, and different from the firstembodiment in the configuration of the constricted part forming member20V. More specifically, the constricted part forming member 20V includesa plate member 40 (corresponding to the inner wall of the presentinvention) instead of the triangular ribs 18 of the above-describedfirst embodiment. The plate member 40 has substantially the same shapeas the vertical cross section 16A of the spiral flow path 16 and isfixed to the support frame 17. A circular center hole 40A is formed inthe center of this plate member 40, with the above-described nozzles 22being arranged in a central part of this center hole 40A. Theconfiguration of this embodiment also provides the advantageous effectssimilar to those of the first embodiment.

Fifth Embodiment

This embodiment is illustrated in FIG. 7, and different from the secondembodiment in the configuration of the constricted part forming member20W. More specifically, the constricted part forming member 20W includesa funnel member 41 (corresponding to the inner wall of the presentinvention) attached to the support frame 17 instead of the plate member40 of the above-described fourth embodiment. This funnel member 41 isformed such that the plate member 40 of the fourth embodiment is curvedinto a funnel shape. A partition bar 17D is attached across the centerhole 41A of the funnel member 41, with a plurality of nozzles 22 beingprovided to this partition bar 17D similarly to the above-describedfirst embodiment. The configuration of this embodiment also provides theadvantageous effects similar to those of the first and secondembodiments.

Example

Tests were conducted as follows with a simulator.

A. Test Method

(1) A model that is the cyclone dust collector 10 of the above-describedfirst embodiment with all the nozzles 30 being removed was set asExample Product 1 of the present invention in the simulator.

(2) A model that is the cyclone dust collector 10 of the above-describedfirst embodiment with the constricted part forming member 20, nozzles 22of the nozzle assembly 50, and nozzle 30 behind the triangular ribs 18being removed was set as Comparative Product 1 in the simulator. Theremaining three nozzles 30 were placed at the starting point of thespiral flow path 16 where the nozzles 22 had been arranged, at alocation 180° turn along the spiral flow path 16 from this startingpoint, and at a location 180° turn further from this position along thespiral flow path 16.

(3) Paint mist particles were set as Particulate 1, while water mistparticles were set as Particulate 2, with their sizes and specificgravities specified as follows in the simulator:

Particulate 1: Diameter 30-40 [μm], Specific gravity 1

Particulate 2: Diameter 30-40 [μm], Specific gravity 1

(4) A first distribution diagram was obtained (FIG. 8(A)) as thedistribution of Particulate 1 in a predetermined vertical cross sectionof the entire cylindrical case 12 under a condition where an aircontaining evenly distributed Particulate 1 flowed into Example Product1 with a predetermined first velocity.

(5) A second distribution diagram was obtained (FIG. 8(B)) as thedistribution of Particulate 2 in the predetermined vertical crosssection of the entire cylindrical case 12 under a condition where, withan air that does not contain Particulate 1 flowing into Example Product1 with the first velocity, Particulate 2 was sprayed from nozzles ofExample Product 1.

(6) Based on the first distribution diagram and second distributiondiagram, the proportion of the area of regions where the paint mist ispresent while the water mist is absent in the predetermined crosssection of the entire cylindrical case 12 of Example Product 1 wasdetermined as unmixed rate, and the mixing rate was obtained bysubtracting this unmixed rate from 100%.

(7) Similarly, the first distribution diagram (FIG. 9(A)), seconddistribution diagram (FIG. 9(B)), and mixing rate were determined withrespect to Comparative Product 1.

B. Test Results

The mixing rate of the paint mist and the water mist in Example Product1 was 91.2[%], while the mixing rate of the paint mist and the watermist in Comparative Product 1 was 75.6[%]. This confirms that the mixingrate of the particles of paint mist contained in the air and particlesof water mist is raised according to the present invention. As themixing rate of the paint mist particles and the water mist particles isincreased, both particles can readily join each other, so that it isassumed that the paint mist particle collection efficiency will beimproved from before.

OTHER EMBODIMENTS

The present invention is not limited to the embodiments described above.Other embodiments, for example, such as those described below, are alsoincluded in the technical scope of the present invention. Further, theinvention can be embodied with various changes other than thosedescribed below without departing from the scope of the subject matter.

(1) The cylindrical case 12 of the cyclone dust collector 10 of theabove-described embodiments has a circular cross section, but it mayhave a polygonal or oval cross section.

(2) The cylindrical case 12 of the cyclone dust collector 10 of theabove-described embodiments has a center axis J1 extending in thevertical direction, but the center axis may extend horizontally, or beinclined to the horizontal.

(3) While the intermediate bridge 17C of the first and secondembodiments extends laterally, the intermediate bridge 17C may beconfigured to extend vertically and include a plurality of nozzles 22 onboth lateral sides of the bridge.

(4) While the intermediate bridge 17C divides the vertical cross section16A in two in the first and second embodiments described above, theintermediate bridge 17C may be configured to divide the vertical crosssection 16A into three or more split regions, with the nozzles 22spraying water mist to each of the split regions.

(5) While the intermediate bridge 17C is supported on both sides in thefirst and second embodiments described above, the intermediate bridge17C may have a cantilevered structure. More specifically, for example,the water distribution pipe 14B may have a cantilevered branch pipeextending therefrom with the plurality of nozzles 22 provided on upperand lower faces of the branch pipe.

(6) To make the vertical cross section 16A of the spiral flow path 16narrower, other than the structures of the embodiments described above,a rectangular plate member may be provided, for example, to cover aboutupper half or lower half of the vertical cross section 16A, or abouthalf of the vertical cross section on one of the left and right sides.

(7) While the cyclone dust collector 10 of the embodiments describedabove is used for removing paint mist particles from air, the presentinvention may be applied to cyclone dust collectors that have othertarget particles to be removed than paint mist from air.

(8) While in the cyclone dust collector 10 of the above describedembodiment, the triangular ribs 18 are arranged on the both corners onthe upper side of the vertical cross section 16A, the triangular ribsmay be arranged on any one, two, three, or all of the four corners ofthe vertical cross section.

(9) While in the cyclone dust collector 10 of the above describedembodiment, the triangular ribs 18, the plate member 40, and the funnelmember 41 may be fixed inside the cylindrical case 12 via the supportframe 17, they may be directly fixed to the cylindrical case 12 bywelding, bolts, and so on.

DESCRIPTION OF THE REFERENCE NUMERAL

-   -   10 Cyclone dust collector    -   12 Cylindrical case    -   14A Center pillar    -   15 Spiral guide    -   16 Spiral flow path    -   16A Vertical cross section (first cross section)    -   17C Intermediate bridge    -   17D Partition bar    -   19 Constricted part    -   22, 30 Nozzle    -   50, 50V, 50W, 50X Nozzle assembly    -   51A, 51B Split region    -   J1 Central axis

What is claimed is:
 1. A cyclone dust collector that includes, inside acylindrical case, a spiral flow path defined by a spiral guide and anozzle that sprays water mist, to combine particles to be removed thatare contained in an air passing through the spiral flow path with thewater mist and to centrifugally collect the particles on an innersurface of the cylindrical case for recovery, the cyclone dust collectorcomprising: a nozzle assembly including a plurality of the nozzlesarranged within a first cross section defined by a plane containing acenter axis of the cylindrical case and part of the spiral flow pathintersecting with each other, the nozzles being adapted to spray thewater mist in a direction along the first cross section; a partition barthat partitions the first cross section into a plurality of splitregions, wherein the plurality of nozzles of the nozzle assembly areattached to the partition bar to spray the water mist to each of theplurality of split regions; and a center pillar that extends along acentral part of the cylindrical case, wherein: the partition bar extendsbetween the center pillar and an inner side face of the cylindricalcase, and the plurality of nozzles of the nozzle assembly are gatheredat a substantially central position in a longitudinal direction of thepartition bar to spray the water mist radially from the substantiallycentral position.
 2. The cyclone dust collector according to claim 1,wherein the nozzle assembly is arranged at an upstream end portion ofthe spiral flow path.
 3. The cyclone dust collector according to claim1, wherein all of the plurality of nozzles inside the cylindrical caseare arranged closer to an upstream side of the spiral flow path.
 4. Thecyclone dust collector according to claim 2, wherein all of theplurality of nozzles inside the cylindrical case are arranged closer toan upstream side of the spiral flow path.
 5. The cyclone dust collectoraccording to claim 1, wherein the cyclone dust collector includes aninner wall arranged on an edge portion of the first cross section andadapted to make the part of the flow path narrower, and the nozzleassembly is arranged in a constricted part of the part of the spiralflow path that is made narrower by the inner wall.
 6. The cyclone dustcollector according to claim 2, wherein the cyclone dust collectorincludes an inner wall arranged on an edge portion of the first crosssection and adapted to make the part of the flow path narrower, and thenozzle assembly is arranged in a constricted part of the part of thespiral flow path that is made narrower by the inner wall.
 7. The cyclonedust collector according to claim 3, wherein the cyclone dust collectorincludes an inner wall arranged on an edge portion of the first crosssection and adapted to make the part of the flow path narrower, and thenozzle assembly is arranged in a constricted part of the part of thespiral flow path that is made narrower by the inner wall.